Robert s



- (No Model.)

R. .S. CARR. TRAIN TELEPHONE.

No. 4423799. Pateited Dec. 16. 1890.

R\ I N Mam ' esse V V %b Inventor Attorney UNITED STATES PATENT OFFICE.

ROBERT S. CARR, OF I-IAMILTON, OHIO, ASSIGNOR OF TWO-THIRDS TO XV. B. CARR AND GEORGE P. STEVENSON, BOTH OF SAHE PLAOE.

TRAlN-TELEPHONE.

SPECIFICATION formng part of Letters Patent No. 4423799, dated December 16, 1890.

Application filed February 1'7, 1890. Serial No. %0,762. (No model.)

.To all whom it may concern:

Be -it known that I, ROBERT S. CARE, of Hamilton, Butler County, Ohio, have invented certain new and useful Improvements in Train-Telephones, of which the following is a specification.

This invention relate's to a system of communication between a locomotive-engineer and the conductor in the cars forming his train, or between the conductor in one car ot the train and a person in another car of the train. The communication s effected through the medium of tubes containing air under pressure, the mouth-pieces and ear-pieces of the tube being` provided with diaphragms. It is preferable for economical reasons to utilize the tubes and air employed in the ordinary air-brake system, and I so exemplify my invention.

My inventon will be readily understood from the following description, in which- Figure l is a side elevation of a portion of a locomotive with one carattached, portions of the locomotive and car appearing in vertical section to expose more fully the telephonic apparatus arranged within the car and within the cab of thelocomotive; Fig. 2, a vertical section of a portion of the locomotivecab, on an enlarged scale, exhibiting the interior telephonic apparatus, &0.; Fig. 3, a side elevation,half-diametrical section, of one of the mouth-pieces, on an enlarged scale; Fig. 4:, a side elevation of a knocker-pin, exemplifying a signaling device forcalling attention when the apparatus is to be used.

In accompanying drawings, A indicates a railway-car, of which there may be any proper number connected in a train; B, alocomotive attached to the car; C, the usual air-reservoir attached to the locomotive; D, the usual engineer s brake-valve in the cab of the locomotive; E, the usual pipe placing this valve in communication with the air-reservoir; F, the usual train-pipe placing the engineefis valve in communication with brake apparatus under all cars of the train; G, continuing portions of such train-pipe under the tender and cars of the train; H, flexible pipes connecting the train-pipe at the junctures between the locomotive and cars and between the several cars which maybe in the train; J, the

usual brake apparatus under the car or several cars, this brake apparatus being in communication with the train-pipe in the usual manner, not necessary' to be particularly shown or described in connection with the present invention; K, the usual pipe through which the air-brake system receives its supply of air under compression, such pipe usually leading from an air-pump attached to the locomotive; L,ap`ipe in the cab connected with the train-pipe and, like the train-pipe, containing air under pressure; M, a telephonic mouth-piece connected with the pipe L and therefore with the train-pipe; N, a similar mouth-piece also in communication with the pipe L, the intention being that the mouthpiece M shall be used to talk into,while the mouth-piece N shall serve as an ear-piece to be listened at, the preferable arrangement being such that these two mouth-pieces are so disposed as to be convenient at once to the mouth and ear of the user; O, a portion of theinterior of the car; P, apipeleading from the train-pipe under the car to the interior of the car; Q, a mouth-piece, like mouthpiece M, in communication with pipe P; R, a mouth-piece, like mouth-piece N, also communicating with pipe P, the intention being that the mouth-pieces Q and R shall serve, respectively, as mouth and ear pieces, as above mentioned, in connection with mouth-pieces M and N; S, a strong diaphragm in each mouthi piece of the system, one side of said diaphragm being open and exposed to the mouth-piece, while the other side is in free communication with and is exposed directly to the pressure of air within the pipe to which the mouthpiece is connected, and T a knoeker-pin which may be employed in tapping on a diaphragm of a mouth-piece to produce a callingsignal, thisknocker-pin being intended merely to exemplify a knocking device.

The train-pipe containing air under pressure, one side of all the diaphragms ofthe mouthpieces will be subjected to this pressure, and the daphragms must be air-tight and strong enough to resist the pressure. The conductor knocking` on the diaphragm of the mouth-piece Q or R in car A or in any other car which may be in the train produces vibrations of the diaphragm knockcd on, and these vibrations are IOO transmitted by means of conpressed air within the train-pipe to all of the other daphragms of the system. The knocking may be done by the knoeker-pin T or by any othcrinstrument or deviee adapted for the purpose. Ali the diaphragms of the system will thus give out the transmitted sound, and an agreed code of signais may serve to indicate What is meant by the knocking. One knock may be a signal for the engineer to give attention to the telephone, two knocks for the condnctor, the., and a signal-code may be arranged by means of which messages may be transmitted between parties empioying the system. The called party, hearing his call, responds by appropriate knocks; but it is not eontenplated that utility of the system shall be thus limited to the transmission of the code-signals by knocks. The calling knoeks having brought the proper parties into communication by means of the system, the parties will then proceed to employ the system for Vocal commu nication, one party talking into his mouthpiecc While the other party listens at his mouth piece, &0. The use of the two mouth-pieces at each point of communication, one for the mouth and one for the ear, is designed simply to facilitate the com'nunication. ltis obvious that a single mouth-piece at each point may be employed, it being used alternateiy as a mouth-piece and as an ear-piece.

In practice with my invention I have oniy enployed conpressed air or in connection with the air-brake system oi' the railwaytrains; but I contenplate that the result Will be cquaily satisfactory in connection with steam as empioyed in steam-b'akes or the steam-heating systems of raiiway-trains, and if steam should prove an efficient medium as a substitute for air in my invention I Would then consider that stean Was the equivalent of eompressed air, and I thus at present contemplate it.

I claim as my inve1tion- In a trairteleplone, the comhinaiion, substan tially as set forth, of a locomotive and car, each provided with an air-pipo, a flexiblepipe connccting said two pipes, air-brake mechanisn upon the car connected With the air-pipe of said car, an air reservoir and valve at said locomotive in communication With said airpipe thereof, mouth-pieces in said locomotive and car in communication with the air-pipes thereot', and a diaphragm in each mouth-piece exposing one side to its moutlrpieee and the other side to the compressed air which may be contained in said air-pipes.

ROBERT S. CARE \Vitnesses:

J. W. SEE, A. C. Roenns. 

